Page Thumbnails Doesn't Appear

Here’s the Code

<?php if(has_post_thumbnail()):?>
<?php $image = wp_get_attachment_image_src(get_post_thumbnail_id(), 'full');?>
<img src="<?php bloginfo('template_directory');?>/style/timthumb.php?src=<?php echo $image[0];?>&w=640&h=230&zc=1" class="alignleft" />
<?php endif;?>

first things first, i used timthumb bcause i have more then one size of thumbnails and seens to be easy this way and have crop, the default set_image_size or whatever related doesn’t have a properly crop.
no big deal, the problem is, i’m using this to get a PAGE thumbnail, not a post thumbnail, but, they act like doesn’t have any thumbnail related to the page :\